eBoot PVC Rubber Pin Backs, Black (100) Size: 12 mm in diameter, 7 mm in height Material: PVC rubber Fits for all lapel pins, tie tacks, citation bars, service bars and jewelry Replacement for pin clutch backs Good for jewelry making and DIY fun; The rubber pin backs are only compatible with the pin 1-1.2 mm in thickness, it can't fasten if the pin is too slim